Lamp-positioning device



Patented July 13, 1937 Winter-ton E. Day, Aipiaus, N. Y., nor to General Electric Company, a corporation of New York Application September il, i935, l

(Cl. 24th-44.25)

3 Claims.

My invention relates to lamp-positioning devices and more particularly to lamp-positioning devices for projectors in which the positioning of the lamp with respect to the reflector changes the character of the light beam.

One object of my invention is to provide a mechanism responsive to an energization of the lamp to change the position of the lamp.

Another object of the invention is to provide a mechanism operable to move the lamp through successive predetermined positions in response to successive energizations of the lamp.

For a better understanding of my invention, together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. l is a diagrammatic illustration of the lamp-positioning mechanism, together with the reflector, lamp and the electrical diagram of connections for the lamp and positioning mechanism; Fig. 2 is a perspective view of the positioning mechanism; Fig. 3 is a side view of the mechanism, partly in section, and Fig. 4 is an enlarged perspective of the positioning cam oi the mechanism.

Referring to Fig. 1 in detail, a lamp lil is illustrated as being in a position behind the ocal point II of a mirror I2. The lamp is shown in a second position, in dotted lines, having its niament I3 coinciding with the focal point il of the mirror I2. Due to the shape of the mirror l2, which is paraboloidal, the beam projected, when the lamp filament is in the illustrated position,

behind the focus of the mirror, is a wide beam suitable for flood-lighting great areas at close range. When the lamp is in the dotted position, the beam is narrow and useful for long range work. It is desirable at times to change the projected beam without making the adjustments at the projector, and in accordance with my improved mechanism such change can be made by successively opening and closing a lamp switch I4 at a control station. The mechanism by which this is accomplished may be understood by reference to Figs. 2 and 3 of the drawing.

Fig. 2 illustrates a portion of a projector housing I5 in which the mechanism is mounted. The mechanism comprises a base I6 having a pair of parallel prongs VI and I8 attached thereto and projecting vertically above said base at one end thereof. A pair of arms I9 and 2i] are pivoted on the prongs at 2l and 22 respectively and may oscillate between the prongs of the U-shaped nbers and mounted on the arms i9 and respectively and arranged to engage the sides ci the vertical prongs il' and i8, thereby limitthe movement of the arms in either direcr'Ehe arms i3 and E@ are fastened to each other by an intermediate member 25 upon which a socket is mounted. The lamp socket be oi desired structure suitable for the base oi the lamp used. in the present illustration it comprises a pair of blocks 2l into which the prongs of the lamp are clamped by means of a thumb screw The lamp support just described is moved to either oi its 'positions and held there by a cam 2Q provided with cam surfaces 3S and 3i, one or the other of which engages a tongue 32 on the cross bar 25. The cam is mounted on a U- shaped rocking member which is pivoted on pins mounted in the prongs il and lil. The cam is further provided with a slot having hooked ends 3S and 35 to accommodate an operating pin The operating pin is mounted in the iree end of a linl; 33 of a toggle mechanism including the links 38, 39 and 1li). The link is pivoted t one end to a rigid support ill by a pin supports the core 43 oi an operating coil which is pivoted thereto by a pin Link is pivoted to link i9 by a pin and links and Sil are pivoted by means oi a pin ill which slides in a slot fi-.i3 of a guide i l Springs connected between the rocking aber and the lower end of link 38 holds the cam 2Q, together with its support on either side oi the pivot pins 34.

The core d3 is lowered every time its solenoid or coil is energized. At this same time the links 33, 39 and il@ are lowered. Assuming the mechanism to be in the position illustrated in Figs. 2 and B, the operating pin 3l hooks into the end oi the slot Sii and pulls member 5:9 and its support 33 about the pivot pins 34. As soon as springs pass the pivot pins they snap the i.-ember 29 into its new position. At this instance the cam surface 3l strikes the tongue and moves the lamp support until it is stopped by the stops and ifi engaging the prongs il and respectively.

When the solenoid irl is deenergized, the springs raise the entire toggle mechanism, and operating pin slides to the upper end of the it must noted that the upper surface of the slot is smooth and permits a free movement of the pin Si?, while the lower side of the slot has the hooked ends and St into which the pin 31 descends and thereby forms a rigid connection between the toggle and the positioning member during the downward movement of the toggle mechanism. Upon a subsequent energization of the coil 44, the above-described operation is repeated and the lamp thereby moved back to its original position.

For the purpose of reducing the current required'by th-e lamp mechanism, during operation of the lamp, an auxiliary coil I and lever 52 are provided and arranged to open the circuit to coil 44 and hold it open during the operation of the projector. For this purpose the lever 52 is pivoted at pin 53 and supports an armature 54. When the core 43 descends, it engages the lever 52 and moves the armature 54 into engagement with the core 56 of the auxiliary coil 5I which is energized simultaneously with the lamp I0. A switch 51 connected into the circuit of the coil 44, as illustrated in Fig. l, is opened by the lever 52 through an operating rod 58. As soon as this switch is open the coil 44 becomes deenergized and permits the armature 43 and the toggle mechanism to rise in response to the action of the springs 50.

The circuit for the device is illustrated in Fig. 1. The switch I4 is the main operating switch and when closed, conducts current from any suitable mains 58 to conductors 59 and 60. Current is thereby led to the lamp Ill by conductors 6I and 62, to the auxiliary coil 5I through a resistor 63, and to the operating coil 44 through switch 51. When the switch I4 is, therefore, rst closed, the mechanism is operated to change the position of the lamp as above explained. This change may bring the lamp into focus or out of focus depending upon what position it was in before the energization of the coils. If the mechanism is in the position illustrated in Figs. 2 and 3, the rst energization of the coils will move the lamp into focus with the Inirror. As long as the switch I4 remains closed and current flows through the circuits of the auxiliary coil, the operating coil remains deenergized. When the switch is opened, however, the armature 52 is released thereby closing the operating coil crcuit, and the operating coil may again be energized at the next closing of the switch I4. When the coil 44 was deenergized the pin 31 moved to the upper end of the slot 35. When the switch I4 is again closed the pin 31 hooks into the end 36 of the slot 35 and pulls down the cam until its cam surface 30 engages the tongue 32 and moves it into the position illustrated in Fig. 2.

For the purpose of manually operating the mechanism, an operating hook 65 is provided. The hook 65 projects through a bushing 66 in the wall of the casing I5 and is provided with a handle 61. The hook is normally raised by a spring 68, but when pulled down it engages the pin 41 on the toggle mechanism. The resulting operation is the equivalent to an energization of the coil 44.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a light projector, the combination of a reflector, a lamp, a pivoted support therefor whereby the lamp may be moved to either one of a plurality of predetermined positions with respect to said reilector, a current circuit for said lamp, a switch in said circuit and means responsive to successive closures of said switch and corresponding energizations of said lamp for moving said support to its predetermined positions successively.

2. In a light projector, the combination of a reflector having a focus, a lamp, a circuit therefor and a switch arranged to open and close said circuit, a pivoted support for said lamp arranged to move said lamp into and out of focus with said reflector, and means responsive to successive closures of said switch and corresponding energizations of said lamp for alternately positioning said lamp in and out of focus with said reilector.

3. In a light projector, the combination of a housing, a reiector, a lamp, a lamp-positioning means in said housing, said positioning-means including a support for said lamp operable to several positions, in each of which positions said lamp is held in a predetermined relation to said reilector, a cam operable to move and hold said support in its several positions respectively, a toggle mechanism arranged to engage said cam at points dependent upon the position of said cam, means responsive to energizations of said lamp for operating said toggle, and means projecting through the wall of said housing for manually operating said toggle mechanism independently of said first operating mechanism.

WINTERTON J. DAY. 

